Minor Bug with the Shop
This is likely to do with the LoL spaghetti code, because I can't understand why it would be coded this way. There appears to be two sets of records detailing the items owned by each player in-game. The first is accurate, and is what dictates which items appear in your inventory and have their effects in-game. The other is used to put a little tick in the shop next to all the items that a player currently owns. The only reason I can think this exists is to make it a little easier to also show the tick next to component items that make up the currently owned items. There's a minor bug with this list: purchasing an item seems to permanently keep it in that list, leaving the tick next to it for the duration of the game. There is barely any drawback to this bug, however. The only one I was able to find is that in the advanced statistics after a game, the vision score can artificially be increased by buying and selling control wards repeatedly.